Assessment of northern mummichog (Fundulus heteroclitus macrolepidotus) as an estuarine pollution monitoring species

Abstract

The use of multiple spawning fishes in environmental effects monitoring programs has proven difficult for a number of reasons including the inability to predict reproductive investment and ensure synchronous sampling of reference and impacted populations. The estuarine resident northern mummichog (Fundulus heteroclitus macrolepidotus) has been successfully used as a sentinel for effects of pulp and paper mill effluents in Atlantic Canada and has been proposed for monitoring other anthropogenic impacts. This study investigated the spatial and temporal variability of the somatic parameters used to describe fish performance, specifically measures of energy use and storage, in estuaries located in Prince Edward Island, Canada. Three sites with varying levels of agricultural input were studied. Fish at all sites depleted their energy reserves over winter, as reflected in depressed condition, liver size, and gonad size, but then quickly replenished them in May. These population parameters were highly variable throughout the reproductive season and within an estuary. Spawning was continuous at all sites without indication of lunar or other periodicity. We conclude that repeated sampling is required to assess reproductive output in the northern mummichog and densities of adults and young-of-the-year deserve further investigation as a potentially less logistically demanding indicator of eutrophication. © 2009, CAWQ.